Attention is paid to effective utilization of biomass energy as a preventive measure for global warming. Above all, since biomass energy derived from plants can effectively use carbon fixed from carbon dioxide in the atmosphere by photosynthesis during the growth process of plants, it has a property which is the so-called carbon neutrality and does not contribute to an increase in carbon dioxide in the atmosphere from the viewpoint of the life cycle.
The utilization of such biomass energy has been widely studied even in the field of a transportation fuel. For example, if a fuel derived from an animal or vegetable oil can be used as a diesel fuel, it is expected to play an important role in the reduction of carbon dioxide emission by the synergistic effect with the high energy efficiency of a diesel engine. As a diesel fuel using an animal or vegetable oil, generally known is a fatty acid methyl ester oil (abbreviated as FAME from the initial letters of fatty acid methyl ester). FAME is manufactured by subjecting a triglyceride, which is a general structure of an animal or vegetable oil, to ester exchange with methanol by the action of an alkali catalyst or the like.
However, as described in Patent Document 1, it is pointed out that the process for manufacturing FAME has problems. For example, a by-product glycerin is required to be treated and cost and energy are required for cleaning of a product oil, or the like.
In addition, since FAME has two oxygen atoms in the molecule, it has an extremely high oxygen content as a fuel. Therefore, another problem thereof is that there is concern that the oxygen content may adversely affect the engine material even when FAME is used by blending it with a conventional diesel fuel derived from petroleum.
Consequently, a method of manufacturing a fuel oil comprising a hydrocarbon which contains substantially no oxygen by hydrodeoxygenating a feedstock oil containing an oxygen-containing hydrocarbon compound derived from an animal or vegetable oil in the presence of a hydrotreatment catalyst is studied (for example, refer to Patent Document 2 and Patent Document 3).